FEMINIZATION OF NILE TILAPIA OREOCHROMIS NILOTICUS BY ORAL ADMINISTRATION OF SEX REVERSAL HORMONE

Hamdoon, N.T.; Zayed, A.E.

doi:10.21608/avmj.1998.183199

FEMINIZATION OF NILE TILAPIA OREOCHROMIS NILOTICUS BY ORAL ADMINISTRATION OF SEX REVERSAL HORMONE "DIETHYLSTILBESTROLE

Document Type : Research article

Authors

N.T. Hamdoon ¹
A.E. Zayed ²

¹ Dept. of Genetics Fac. of Agriculture, Assiut University

² Dept. of Anat. and Histol., Fac. of Vet. Medicine

10.21608/avmj.1998.183199

Abstract

Induction of sex reversal in Oreochromis niloticus by diethylstilbestrol (DES) and its effect on growth promotion was studied at two different hormone doses, 50mg and 100mg/kg of feed for two different feeding duration of 25 and 40 days. Treated and untreated (control) groups were
sexed using the standard gonadal squash technique and sex ratio was calculated. The basic structure of both testis and ovary at the time of sexing was microscopically studied in semithin sections. The testis was found to be composed of lobules separated by connective tissue septa. Each lobule contained spermatogonia, primary spermatocytes, secondary spermatocytes and spermatids. The ovary displayed the presence of many ovarian follicles at different stages of development in addition to some oogonial cell nests. Both DES levels and feeding duration led to significant increases in female percentage as compared with the control group < /strong>. The obtained results indicated that using 100mg/kg DES dose for 40 days feeding duration produced the highest percentage of females. In addition, the oral administration of DES variably affected individual fry weight, specific growth rate (SGR) and percentage of survival.